Locking device for telescopic displaceable tubes



FIG. 1 is a side elevation of a locking device embodying my new design;

FIG. 2 is an elevation thereof, as viewed from the right-hand side of FIG. 1;

FIG. 3 is an elevation thereof, as viewed from the left-hand side of FIG. 1; and

FIG. 4 is a vertical section thereof, taken on the plane 4--4, indicated in FIG. 1. 

The ornamental design for a locking device for telescopic displaceable tubes, substantially as shown and described. 